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"""Add cascade to dag_tag foreign key.

Revision ID: 3c94c427fdf6
Revises: 1de7bc13c950
Create Date: 2022-05-03 09:47:41.957710

"""

from __future__ import annotations

from alembic import op
from sqlalchemy import inspect

from airflow.migrations.utils import get_mssql_table_constraints

# revision identifiers, used by Alembic.
revision = "3c94c427fdf6"
down_revision = "1de7bc13c950"
branch_labels = None
depends_on = None
airflow_version = "2.3.2"


def upgrade():
    """Apply Add cascade to dag_tag foreignkey."""
    conn = op.get_bind()
    if conn.dialect.name in ["sqlite", "mysql"]:
        inspector = inspect(conn.engine)
        foreignkey = inspector.get_foreign_keys("dag_tag")
        with op.batch_alter_table(
            "dag_tag",
        ) as batch_op:
            batch_op.drop_constraint(foreignkey[0]["name"], type_="foreignkey")
            batch_op.create_foreign_key(
                "dag_tag_dag_id_fkey", "dag", ["dag_id"], ["dag_id"], ondelete="CASCADE"
            )
    else:
        with op.batch_alter_table("dag_tag") as batch_op:
            if conn.dialect.name == "mssql":
                constraints = get_mssql_table_constraints(conn, "dag_tag")
                Fk, _ = constraints["FOREIGN KEY"].popitem()
                batch_op.drop_constraint(Fk, type_="foreignkey")
            if conn.dialect.name == "postgresql":
                batch_op.drop_constraint("dag_tag_dag_id_fkey", type_="foreignkey")
            batch_op.create_foreign_key(
                "dag_tag_dag_id_fkey", "dag", ["dag_id"], ["dag_id"], ondelete="CASCADE"
            )


def downgrade():
    """Unapply Add cascade to dag_tag foreignkey."""
    conn = op.get_bind()
    if conn.dialect.name == "sqlite":
        with op.batch_alter_table("dag_tag") as batch_op:
            batch_op.drop_constraint("dag_tag_dag_id_fkey", type_="foreignkey")
            batch_op.create_foreign_key("fk_dag_tag_dag_id_dag", "dag", ["dag_id"], ["dag_id"])
    else:
        with op.batch_alter_table("dag_tag") as batch_op:
            batch_op.drop_constraint("dag_tag_dag_id_fkey", type_="foreignkey")
            batch_op.create_foreign_key(
                None,
                "dag",
                ["dag_id"],
                ["dag_id"],
            )
